My career goal is to become a competent veterinary clinician-researcher and to study pathophysiological mechanisms of cardiac diseases. As a board certified veterinary cardiologist, I have received thorough veterinary clinical training, with emphasis on cardiac disease. However, to become an effective, independent researcher, I need rigorous, basic research training, followed by an orderly transition to research independence. To achieve these goals, I propose a research training program under the co-sponsorship of Dr. Harvey Sparks, who is a highly successful trainer and an expert in coronary blood flow, and Dr. Robert Serphenson, who is successfully training students in unique techniques for study of reflex regulation of the circulation in conscious dogs. My aim in Phase I is to complete the Ph.D. Program in cardiovascular Physiology that I began in 7/85. Phase I research is designed to test the hypothesis that chronic heart failure causes hemodynamic instability by impairing the ability of the arterial baroreceptor reflex to control both cardiac output and peripheral vascular resistance. Dogs will be surgically prepared for subsequent, reversible carotid sinus isolation. Complete stimulus-response relations for the carotid baroreflex will be determined for the first time in conscious dogs before, during, and following the reversal of pacing-induced chronic heart failure. My aim in Phase II is to make an orderly and productive transition from working as a research associate to establishing an independent program of basic and clinical research on cardiac pathophysiology. Research in Phase II is designed to test the hypothesis that a brief period of myocardial ischemia causes impairment of arterial baroreflexes in conscious dogs through increased activation of cardiac ventricular receptor reflexes, which interact centrally with the arterial baroreflex. Myocardial ischemia will be induced by 45-second coronary occlusions, and responses will be compared during normal reflex operation, during isolation of the cartoid sinuses at various pressures, and during interruption of afferent neural pathways from the cardiac ventricles. This research is important because impairment of normal baroreflex function is likely to contribute to the instability of blood pressure, cardiac output, and total peripheral resistance that frequently complicated cardiac disease.